1. Field of the Invention
The present invention relates to fields of semiconductor technology and, more particularly, relates to a chemical mechanical polishing device and a polishing apparatus.
2. Description of Prior Art
Chemical mechanical polishing (CMP) was introduced into integrate circuit fabrication industry by IBM in 1984, and firstly was applied in planarization of inter metal dielectric (IMD) in back-end process, and then was applied in planarization of tungsten through improvement of device and technique, subsequently was applied in planarization of shallow trench isolation (STI) and cuprum. CMP is an active technique in IC fabrication during recent years.
The mechanism of CMP is that surface material of a polished wafer chemically reacts with polishing slurry to form a correspondingly easily removed surface layer, which can be mechanically polished away with relative movement between the surface layer and a polishing pad through abrasives in the polishing slurry and polishing pressure put on the polished wafer. Specially, when performing CMP on metallic material, the polishing slurry contacts the surface of the metallic material to form metal oxides, and the metal oxides are removed to reach polishing effect.
A CMP device in the prior art is illustrated in FIG. 1. A polishing apparatus of the CMP device includes a polishing plate 102 that automatically rotates and a wafer holder 104. Generally, the polishing plate 102 is designed as a round plate in order to rotate with a polishing pad 106 which is fixed on the polishing plate 102. A wafer 110 that is provided is held by the wafer holder 104 whose position can be adjusted. The wafer holder 104 provides a pressure on the wafer 110 to ensure that the wafer 110 contacts the polishing pad 106 during polishing. A slurry supply route 108 laid upon the polishing plate 102 provides polishing slurry 112 which includes a reactant and an abrasive. The reactant is used for reacting with the surface material of the wafer 110 to form material which can be correspondingly easily polished away. The abrasive is used for mechanical polishing between the polishing pad 106 and the wafer 110. There is usually an adjustor 114 for adjusting the polishing pad 106 in the CMP device.
However, for reducing cost of fabricating a single chip, the size of a wafer is increased, e.g., from 8 inches to 12 inches, or to 18 inches, or even to 24 inches or greater. The increased size of the wafer makes it difficult to uniformly polish the wafer using a CMP technology, especially for polishing the edge of the wafer. In addition, the polishing apparatus of the CMP device may have a large size as the wafer size increases, which may adversely affect miniaturization of the device and may adversely affect maintenance of the CMP device.